Active energy balancing for energy storage systems

1. A system, comprising: a first circuit coupled with a first battery cell and a second battery cell, the first circuit comprising: a first charge unit to store energy transferred between the first battery cell and the second battery cell, the first charge unit comprising a resistor in parallel arrangement with an inductor, the resistor coupled with a first node of the first charge unit and a second node of the first charge unit and the inductor coupled with the first node of the first charge unit and the second node of the first charge unit; the first node of the first charge unit coupled with the first battery cell and with the second battery cell and the second node of the first charge unit coupled with a first transistor of the first circuit; and a second transistor of the first circuit coupled with the second node of the first charge unit, wherein at least one of the first transistor of the first circuit and the second transistor of the first circuit are to: control a first transfer of the energy from a first one of the first battery cell or the second battery cell to the first charge unit to store the energy via the inductor and the resistor; and control a second transfer of the energy from the first charge unit via the inductor and the resistor to a remaining one of the first battery cell and the second battery cell; a second circuit coupled with the second battery cell and a third battery cell, the second circuit comprising a second charge unit to store energy transferred between the second battery cell and the third battery cell, the second charge unit comprising a first node of the second charge unit coupled with the second battery cell and the third battery cell and a second node of the second charge unit coupled with a first transistor of the second circuit and a second transistor of the second circuit to control energy transfer between the second battery cell and the third battery cell via the second charge unit; and a third circuit coupled with the second battery cell and a fourth battery cell that is not directly coupled with the first circuit or the second circuit, the third circuit comprising: a third charge unit: a first node of the third charge unit coupled with the second battery cell and a second node of the third charge unit coupled with a first transistor of the third circuit and a second transistor of the third circuit that is coupled with the fourth battery cell, at least one of the first transistor of the third circuit or the second transistor of the third circuit to: control a third transfer of the energy from the remaining one of the first battery cell or the second battery cell to the third charge unit of the third circuit to store the energy in the third charge unit; and control a fourth transfer of the energy from the third charge unit to the fourth battery cell; and a controller configured to cause the first transfer and the second transfer to be completed within a first cycle and the third transfer and the fourth transfer to be completed within a second cycle.

2. The system of claim 1, comprising: a second resistor coupled with the first battery cell and with a circuit comprising a transistor configured to selectively dissipate, via the second resistor, a portion of energy stored at the first battery cell in response to the first battery cell achieving full charge before the second battery cell achieves the full charge.

3. The system of claim 1, wherein the first node of the first charge unit is coupled with a positive terminal of the first battery cell and a negative terminal of the second battery cell, and wherein the first node of the second charge unit and the first node of the third charge unit are each coupled with a positive terminal of the second battery cell and a negative terminal of the third battery cell.

4. The system of claim 1, wherein the first transistor of the third circuit is coupled with a fifth battery cell that is not directly coupled with the first circuit or the second circuit.

5. The system of claim 1, wherein: the first transistor of the first circuit is a first metal-oxide semiconductor field effect transistor (MOSFET) comprising a first gate coupled with a first input line to control the first transfer of the energy between the first battery cell and the first charge unit; and the second transistor of the first circuit is a second MOSFET comprising a second gate coupled with a second input line to control the second transfer of energy between the first charge unit and the second battery cell.

6. The system of claim 1, wherein the first node of the first charge unit is coupled with the first battery cell of a plurality of battery cells of a first battery module of a plurality of battery modules, and wherein the first node of the first charge unit is coupled with the second battery cell of a plurality of battery cells of a second battery module of the plurality of battery modules.

7. The system of claim 1, wherein at least one of the first transistor of the second circuit and the second transistor of the second circuit are to: control a first transfer of the energy from a first one of the second battery cell or the third battery cell to the second charge unit to store the energy; and control a second transfer of the energy from the second charge unit to a remaining one of the second battery cell or the third battery cell.

8. The system of claim 1, comprising: a battery monitor to monitor operational parameters of the first battery cell, the second battery cell, the third battery cell and the fourth battery cell; and wherein the controller implements the first transfer, the second transfer, the third transfer A and the fourth transfer responsive to the operational parameters.

9. The system of claim 1, comprising: a first input line for the first transistor of the first circuit to trigger, responsive to a signal indicative of a first state of the first cycle, the first transfer of the energy from the first battery cell to the first charge unit; and the first input line for the first transistor to trigger, responsive to a second signal indicative of a second state of the first cycle, the second transfer of the energy from the first charge unit, via a diode of the second transistor of the first circuit, to the second battery cell.

10. The system of claim 9, comprising: a first input line for the first transistor of the third circuit to trigger, responsive to a third signal indicative of a first state of the second cycle, the third transfer of the energy from the second battery cell to the third charge unit; and the first input line for the third transistor to trigger, responsive to a fourth signal indicative of a second state of the second cycle, the second transfer of the energy from the third charge unit, via a diode of the second transistor of the third circuit, to the fourth battery cell.

11. A method, comprising: coupling a first circuit with a first battery cell and a second battery cell, the first circuit comprising a first charge unit for storing energy transferred between the first battery cell and the second battery cell, the first charge unit comprising a resistor in parallel arrangement with an inductor, the resistor coupled with a first node of the first charge unit and a second node of the first charge unit and the inductor coupled with the first node of the first charge unit and the second node of the first charge unit; coupling, by the first circuit, the first node of the first charge unit with the first battery cell and with the second battery cell; coupling, by the first circuit the second node of the first charge unit with a first transistor of the first circuit and with a second transistor of the first circuit; controlling, by the first circuit, a first transfer of the energy from a first one of the first battery cell and the second battery cell to the first charge unit to store the energy via the inductor and the resistor; and controlling, by the first circuit, a second transfer of the energy from the first charge unit via the inductor and the resistor to a remaining one of the first battery cell and the second battery cell; coupling a second circuit with the second battery cell and a third battery cell, the second circuit comprising a second charge unit to store energy transferred between the second battery cell and the third battery cell, the second charge unit comprising a first node of the second charge unit coupled with the second battery cell and the third battery cell and a second node of the second charge unit coupled with a first transistor of the second circuit and a second transistor of the second circuit to control energy transfer between the second battery cell and the third battery cell via the second charge unit: coupling a third circuit with the second battery cell and a fourth battery cell that is not directly coupled with the first circuit or the second circuit: coupling, a first node of a third charge unit of the third circuit with the second battery cell; coupling a second node of the third charge unit with a first transistor of the third circuit and a second transistor of the third circuit that is coupled with the fourth battery cell: controlling, by at least one of the first transistor of the third circuit or the second transistor of the third circuit, a third transfer of the energy from the remaining one of the first battery cell or the second battery cell to the third charge unit of the third circuit to store the energy in the third charge unit; controlling, by the at least one of the first transistor of the third circuit or the second transistor of the third circuit, a fourth transfer of the energy from the third charge unit to the fourth battery cell; and causing, by a controller, the first transfer and the second transfer to be completed within a first cycle and the third transfer and the fourth transfer to be completed within a second cycle.

12. The method of claim 11, comprising: coupling, by a second resistor, the first battery cell and circuit comprising a transistor configured to selectively dissipate, via the second resistor, a portion of energy stored at the first battery cell in response to the first battery cell achieving full charge before the second battery cell achieves the full charge.

13. The method of claim 11, comprising: coupling the first transistor of the third circuit with a fifth battery cell that is not directly coupled with the first circuit or the second circuit.

14. The method of claim 11, comprising: triggering, using a first input line for the first transistor of the first circuit and responsive to a signal indicative of a first state of the first cycle, the first transfer of the energy from the first battery cell to the first charge unit; and triggering, using the first input line for the first transistor of the first circuit and responsive to a second signal indicative of a second state of the second cycle, the second transfer of the energy from the charge unit, via a diode of the second transistor of the first circuit, to the second battery cell.

15. The method of claim 11, comprising: triggering, via a first input line for the first transistor of the third circuit, responsive to a third signal indicative of a first state of the second cycle, the third transfer of the energy from the second battery cell to the third charge unit; and triggering, via the first input line for the third transistor, responsive to a fourth signal indicative of a second state of the second cycle, the second transfer of the energy from the third charge unit, via a diode of the second transistor of the third circuit, to the fourth battery cell.

16. The method of claim 11, comprising: coupling a first gate of a first metal-oxide semiconductor field effect transistor (MOSFET) of the first transistor of the first circuit with a first input line to control the first transfer of the energy between the first battery cell and the first charge unit; and coupling a second gate of a second MOSFET of the second transistor of the first circuit with a second input line to control transfer of energy between the first charge unit and the second battery cell.

17. The method of claim 11, comprising: coupling the first node of the first charge unit with the first battery cell of a first plurality of battery cells of a first battery module of a plurality of battery modules; and coupling the first node of the first charge unit with the second battery cell of a second plurality of battery cells of a second battery module of the plurality of battery modules.

18. The method of claim 11, comprising: controlling, by at least one of the first transistor of the second circuit and the second transistor of the second circuit, a first transfer of the energy from a first one of the second battery cell and the third battery cell to the second charge unit; and controlling, by the at least one of the first transistor of the second circuit and the second transistor of the second circuit, a second transfer of the energy from the second charge unit to a remaining one of the second battery cell and the third battery cell.

19. The method of claim 11, comprising: monitoring, by a battery monitor, operational parameters of the first battery cell, the second battery cell, the third battery cell and the fourth battery cell; and implementing, by the controller, the first transfer, the second transfer, the third transfer and the fourth transfer responsive to the operational parameters.

20. An energy storage system, comprising: a first circuit for energy transfer between a first battery cell and a second battery cell of the energy storage system, the first circuit comprising: a first charge unit of the first circuit to store energy transferred between the first battery cell and the second battery cell, the first charge unit comprising: a resistor coupled with a first node of the first charge unit and a second node of the first charge unit; and an inductor coupled with the first node of the first charge unit and the second node of the first charge unit and arranged in parallel with the resistor; the first node of the first charge unit coupled with a positive terminal of the first battery cell and with a negative terminal of the second battery cell; a first transistor of the first charge unit coupled with the second node of the first charge unit; and a second transistor of the first circuit coupled with the second node of the first charge unit, wherein at least one of the first transistor of the first charge unit and the second transistor of the first circuit are to control transfer of the energy between the first battery cell and the second battery cell, via the inductor and the resistor; a second charge unit to store energy transferred between the second battery cell and a third battery cell, the second charge unit comprising a first node of the second charge unit coupled with the second battery cell and the third battery cell and a second node of the second charge unit coupled with a first transistor of the second circuit and a second transistor of the second circuit to control energy transfer between the second battery cell and the third battery cell via the second charge unit; and a third circuit coupled with the second battery cell and a fourth battery cell that is not directly coupled with the first circuit or the second circuit; a third charge unit of the third circuit; a first node of the third charge unit coupled with the second battery cell and a second node of the third charge unit coupled with a first transistor of the third circuit and a second transistor of the third circuit that is coupled with the fourth battery cell, at least one of the first transistor of the third circuit or the second transistor of the third circuit to: control a third transfer of the energy from the remaining one of the first battery cell or the second battery cell to the third charge unit of the third circuit to store the energy in the third charge unit; and control a fourth transfer of the energy from the third charge unit to the fourth battery cell; and a controller configured to cause the first transfer and the second transfer to be completed within a first cycle and the third transfer and the fourth transfer to be completed within a second cycle.